TAUNTON — Three Taunton police officers joined a heartwarming birthday celebration for a 7-year-old from Rhode Island who is fighting cancer for the second time, in a story that gained national attention on Thursday as hundreds of first responders rallied behind the boy.

Taunton Police Department Patrolmen Jayson LaPlante, Derek Feeney and Ernie Chretien were among about 1,000 police officers, firefighters, rescue workers and military service members who attended a special surprise seventh birthday party for Tyler Seddon.

Seddon, who is battling leukemia for the second time, made a small birthday request to receive cards from his heroes in law enforcement. But his mother shared the wish on social media, which drew response from throughout the region and the country.

“We were really happy to be a part of it, to help make sure it’s a birthday he’ll never forget,” said LaPlante, who is also president of the Taunton Police Mutual Benefits Association, which focuses on giving back to the community. “Here you have a 7-year-old battling cancer. He’s a fighter. He needs every ounce of support he can get.”

LaPlante described an “enormous” motorcade that formed in East Providence, R.I., before descending on Seddon’s birthday party, filling the streets and temporarily shutting down the highway. LaPlante said the Taunton officers met other police officers who came from as far as Kentucky, Virginia Beach and Ohio.

“People came from a long distance to really try to make this kid’s day,” he said.

According to the Rhode Island State Police, Gov. Lincoln Chafee also made Seddon the honorary governor of the state of Rhode Island for the day, and the state police made him an honorary trooper.

LaPlante said it was worth the cause to drive down to Burrillville, R.I., where Seddon lives, to wish the 7-year-old a happy birthday and to deliver a special Taunton Police Department gift basket, including Taunton K9 Division-donated police dog trading cards and a shirt and hat with the Taunton Dive Team insignia.

“All the guys in the department signed a big birthday card,” LaPlante said. “Different guys brought different things for him, including a T-shirt and lots of other things. Everyone kind of pitched in. We were really happy to be a part of it.”